The present invention relates to a contact probe which is used for inspecting a semiconductor integrated circuit and the like, and a socket provided with the contact probe.
In case of conducting inspection of an object to be inspected such as a semiconductor integrated circuit, a contact probe is generally used in order to electrically connect the object to be inspected to a board for inspection provided at a measuring instrument side.
A related-art contact probe will be described referring to FIGS. 7A and 7B. FIG. 7A shows an entire structure of the contact probe. FIG. 7B shows, in an enlarged scale, an encircled part Q in FIG. 7A which indicates an internal contact point of the contact probe. As shown in FIGS. 7A, 7B, the contact probe of this type has such a structure that a first plunger 61, which is a connecting component with respect to the object to be inspected such as the semiconductor integrated circuit, is directly contacted with a second plunger 62, which serves as a connecting component to the board for inspection, for the purpose of reducing a passing resistance of electricity. A contact point between the object to be inspected and the board for inspection is secured by butting the first and second plungers 61, 62 respectively to the object to be inspected and the board for inspection with a spring force generated by compressing a coil spring 63, which is a component of the contact probe. The internal contact point of the contact probe, which corresponds to an engagement point at which a columnar part of the first plunger 61 and a cylindrical part of the second plunger 62 are engaged with each other, has a clearance (play) for smooth sliding movement, as shown in FIG. 7B. For this reason, a contact state has not been stabilized, and the passing resistance has been unstable. JP-A-4-270967 discloses a similar structure.
Moreover, JP-B-6-28699U discloses an art for bringing the first plunger into contact with the second plunger. However, this art cannot be put into practice, in case where diameters of the plungers are further smaller, because working technique with high accuracy is required.
In case of the related-art contact probe as shown in FIGS. 7A and 7B, there is a problem that the passing resistance is unstable due to the clearance of the internal contact point of the contact probe. Moreover, the related-art structure disclosed in JP-B-6-28699U cannot be applied to a case where electrodes are arranged at a small pitch on the object to be inspected such as the semiconductor integrated circuit, because the structure requires the working technique with high accuracy.